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Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Memory lifecycle management
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 5.5 (MEDIUM). Attack characteristics: local attack vector, low complexity, no privileges required, user interaction required. EPSS exploitation probability: 1.15%.

Exploit ScenarioDerived

A local attacker with access to the system could access freed memory to execute arbitrary code or crash the application. No authentication is required to exploit this vulnerability.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 1.2% exploitation probability (EPSS)

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AnalysisAI

Use-after-free vulnerability in the xmlDictComputeFastKey function in libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1, allows. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Use smart pointers or garbage-collected languages. Set pointers to NULL after freeing. Enable memory sanitizers.

Affects your stack

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Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Use After Free (CWE-416), which allows attackers to access freed memory to execute arbitrary code or crash the application. Use-after-free vulnerability in the xmlDictComputeFastKey function in libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1, allows remote attackers to cause a denial of service via a crafted XML document. Affected products include: Canonical Ubuntu Linux, Debian Debian Linux, Apple Iphone Os, Apple Mac Os X, Apple Tvos. Version information: before 2.9.4.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.5 MEDIUM
AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

DescriptionCVE.org

Use-after-free vulnerability in the xmlDictComputeFastKey function in libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1, allows remote attackers to cause a denial of service via a crafted XML document.

Threat Intelligence Overview

EPSS Score
1.2%
Top 21% exploitable
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 1.2%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

29
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +28
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)CVE.org

cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:15.10:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:tvos:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:watchos:*:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:7.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:7.3:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:7.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_eus:7.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_eus:7.3:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_eus:7.4:*:*:*:*:*:*:*
+ 10 more
CVE-2025-6021 HIGH POC
7.5 Jun 12

Stack-based buffer overflow in libxml2's xmlBuildQName function allows remote unauthenticated attackers to crash affecte

CVE-2016-4658 CRITICAL
9.8 Sep 25

xpointer.c in libxml2 before 2.9.5 (as used in Apple iOS before 10, OS X before 10.12, tvOS before 10, and watchOS befor

CVE-2016-1762 HIGH POC
8.1 Mar 24

The xmlNextChar function in libxml2 before 2.9.4 allows remote attackers to cause a denial of service (heap-based buffer

CVE-2016-1834 HIGH POC
7.8 May 20

Heap-based buffer overflow in the xmlStrncat function in libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X b

CVE-2016-1840 HIGH POC
7.8 May 20

Heap-based buffer overflow in the xmlFAParsePosCharGroup function in libxml2 before 2.9.4, as used in Apple iOS before 9

CVE-2022-40303 HIGH
7.5 Nov 23

An issue was discovered in libxml2 before 2.10.3. Rated high severity (CVSS 7.5), this vulnerability is remotely exploit

CVE-2017-9047 HIGH POC
7.5 May 18

A buffer overflow was discovered in libxml2 20904-GITv2.9.4-16-g0741801. Rated high severity (CVSS 7.5), this vulnerabil

CVE-2016-4447 HIGH POC
7.5 Jun 09

The xmlParseElementDecl function in parser.c in libxml2 before 2.9.4 allows context-dependent attackers to cause a denia

CVE-2017-16932 HIGH
7.5 Nov 23

parser.c in libxml2 before 2.9.5 does not prevent infinite recursion in parameter entities. Rated high severity (CVSS 7.

CVE-2016-4483 HIGH POC
7.5 Apr 11

The xmlBufAttrSerializeTxtContent function in xmlsave.c in libxml2 allows context-dependent attackers to cause a denial

CVE-2013-1969 HIGH POC
7.5 Apr 25

Multiple use-after-free vulnerabilities in libxml2 2.9.0 and possibly other versions might allow context-dependent attac

CVE-2016-1839 MEDIUM POC
5.5 May 20

The xmlDictAddString function in libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS befo

References

Advisories & patches
PATCH https://git.gnome.org/browse/libxml2/commit/?id=45752d2c334b50016666d8f0ec3691e2d680f0a0 PATCH https://kc.mcafee.com/corporate/index?page=content&id=SB10170 ADVISORY http://lists.apple.com/archives/security-announce/2016/Jul/msg00000.html ADVISORY http://lists.apple.com/archives/security-announce/2016/Jul/msg00001.html ADVISORY http://lists.apple.com/archives/security-announce/2016/Jul/msg00002.html ADVISORY http://lists.apple.com/archives/security-announce/2016/Jul/msg00003.html ADVISORY http://lists.apple.com/archives/security-announce/2016/Jul/msg00005.html ADVISORY http://lists.apple.com/archives/security-announce/2016/May/msg00001.html ADVISORY http://lists.apple.com/archives/security-announce/2016/May/msg00002.html ADVISORY http://lists.apple.com/archives/security-announce/2016/May/msg00003.html ADVISORY http://lists.apple.com/archives/security-announce/2016/May/msg00004.html ADVISORY http://xmlsoft.org/news.html ADVISORY https://support.apple.com/HT206564 ADVISORY https://support.apple.com/HT206566 ADVISORY https://support.apple.com/HT206567 ADVISORY https://support.apple.com/HT206568 ADVISORY https://support.apple.com/HT206899 ADVISORY https://support.apple.com/HT206901 ADVISORY https://support.apple.com/HT206902 ADVISORY https://support.apple.com/HT206903 ADVISORY https://support.apple.com/HT206904 ADVISORY https://support.apple.com/HT206905 REF http://rhn.redhat.com/errata/RHSA-2016-2957.html REF http://www.oracle.com/technetwork/topics/security/bulletinjul2016-3090568.html REF http://www.oracle.com/technetwork/topics/security/linuxbulletinjul2016-3090544.html REF http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html REF http://www.securityfocus.com/bid/90691 REF http://www.securitytracker.com/id/1035890 REF http://www.ubuntu.com/usn/USN-2994-1 REF https://access.redhat.com/errata/RHSA-2016:1292 REF https://bugzilla.gnome.org/show_bug.cgi?id=759398 REF https://security.gentoo.org/glsa/201701-37 REF https://www.debian.org/security/2016/dsa-3593 REF https://www.tenable.com/security/tns-2016-18

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